Many modern day electronic devices comprise image sensors. Some types of image sensors include frontside illuminated (FSI) image sensors and backside illuminated (BSI) image sensors. A FSI image sensor comprises an array of pixel sensors covered by an interconnect structure, and configured to receive incident radiation (e.g., light) through the interconnect structure. A BSI image sensor comprises an array of pixel sensors overlying an interconnect structure, and configured to receive incident radiation on an opposite side as the interconnect structure. Compared to BSI image sensors, FSI image sensors are more mature. As such, FSI image sensors offer better performance per unit cost and are more common.